CN104709942A

CN104709942A - Simple method for preparing sprayed chrome oxide

Info

Publication number: CN104709942A
Application number: CN201310682049.5A
Authority: CN
Inventors: 裴振昭
Original assignee: Hebei University of Engineering
Current assignee: Hebei University of Engineering
Priority date: 2013-12-16
Filing date: 2013-12-16
Publication date: 2015-06-17

Abstract

The invention belongs to the field of inorganic material preparation and especially relates to a method for preparing sprayed chrome oxide by a surfactant-free hydrothermal method. The method is characterized in that a used oxidizing agent is a metal cation-containing hexavalent chromium compound and a used reducing agent is small molecular alcohol or aldehyde, the reducing agent, the oxidizing agent and water are blended according to oxidizing agent concentration of 40g/l or more and a mole ratio of the reducing agent to the oxidizing agent of 0.2-5, then the reaction system undergoes a reaction at a constant reaction temperature of 140-300 DEG C under hydrothermal conditions for some time and generally for less than 120min, and the precipitates are washed, dried and calcined to form spherical micron-sized sprayed chrome oxide, wherein a calcining temperature is generally in a range of 800-1200 DEG C and calcining time is generally less than 2h. The method has simple processes, is superior to the prior art, and has low energy consumption and a good popularization value.

Description

A kind of simple method preparing spraying chromic oxide

Invention field

The present invention relates to a kind of simple preparation spraying chromic oxide (Cr ₂o ₃) method, particularly relate to a kind of surfactant-free hydrothermal method prepare spraying chromic oxide method.

Background technology

Spraying chromic oxide is similar to spherical, that particle diameter is more than 5 microns chromic oxide (Cr ₂o ₃), Commonly Used Size is 5-200 micron.Be a superior performance, have the high value added product of extensive use and bright application prospect.Its abrasive wear resistance, hard power wearing and tearing and particle erosion, acidproof, alkali, salt and all kinds of SOLVENTS, to air stabilizer pole, hardness is high, frictional coefficient is little, wear-resisting good with polishing performance, it is excellent corrosion and wear resistance layer material, be mainly used in iron and steel long-effective corrosion erosion resisting coating (as large-scale hydraulic steel construction gate, bridge steel structure, ocean army, civilian steel construction etc.), car and shipbuilding industry are (as the stern tube shaft of boats and ships, bearing support, generator, steering wheel, the subsidiary engine axles such as windlass, various valve sealing face, pump shaft cover, plunger, the moving partss such as mechanical seal ring), aviation, space industry (component as very serious in some wear problem of aircraft engine and the high temperature resistant rub resistance parts of nozzle), Iron And Steel Industry is (as continuous annealing furnace roller, hot dip plating line sinking roller, hot rolling instrument) and the energy, nuclear industry is (as Industrial Boiler water wall tube, superheater tube, after heat pipe, cavitation coating of water turbine overflowing component etc.).

But although spraying chromic oxide superior performance, use range are wide, its preparation technology does not obtain large progress for many years.The preparation method used both at home and abroad is at present based on Massachusetts, United States St. Goeben Ceramic & Plastic stocks Co., Ltd patent, utilize melting-crush method and spray-drying process to prepare spraying chromic oxide, our country there is no the independent intellectual property rights in preparation technology.

Massachusetts, United States St. Goeben Ceramic & Plastic stocks Co., Ltd utilizes the method for various heat treating method or dinectly bruning to prepare chromic oxide and alumina composite spray material.Such as by arc process, chromic oxide and alumina powder are fused together, each component powders is combined; Or fuse with plasma body.But good method is the method preparation sintering each component mixture, and temperature is 1250-1500 DEG C, preferably at 1300-1450 DEG C.The general deficient time needs 10-40 hour, preferably at 15-30 hour, finally obtains d ₅₀for the spraying chromic oxide spherical powder of 5-200 μm.But this preparation technology exists length consuming time, consume energy high, complex process, thus cause high in cost of production problem in actual production.

Domestic Xu Xuan is with the chromic oxide coacervate of 100-300nm for raw material, and ball milling 2-8h after mixing with water, then adds 1% ~ 8% organic binder bond, stir, and utilize ultrasonication that slurry is disperseed further.The slurry for preparing adopts atomizer moisture eliminator to carry out drying, controls centrifuge speed and feeding rate well, and the powder collected from cyclone separating tower outlet, through 900 ~ 1200 DEG C of thermal treatments, obtains the aggregate powder of AI/Yt of 45-75 μm.

But spray-drying process also exists shortcoming, one is that particularly microprocess study mechanism is not enough for each process mechanism, in preparation process, there is blindness to the control of processing parameter; Two is that spray-drying process easily produces hollow granule and to break spherical shell, may cause coating damage, come off and the problem such as undercapacity.

Pei Zhenzhao was once also tensio-active agent with CTAB, large-sized chromic oxide that utilized hydrothermal method to prepare, and this technique is lower than front several technique power consumption.But for suitability for industrialized production, parameter is more few is more easy to control quality product, cost is lower.The hydrothermal method preparation spraying chromic oxide technique exploring surfactant-free is obviously significant.

There is more complicated, consuming time longer, the problem such as power consumption is larger of technique based on current spraying chromic oxide industrialized route, we have developed spraying chromic oxide surfactant-free hydrothermal method new preparation process.

Summary of the invention

The object of the invention is to solve more complicated, consuming time longer, the problem such as power consumption is larger of the technique existed in spraying chromic oxide preparation at present, realize preparation condition that is simpler, low cost.A kind of simple method preparing spraying chromic oxide of exploitation, namely under hydrothermal reaction condition, not need to add tensio-active agent for background, prepare chromium hydroxide through redox reaction, chromium hydroxide obtains through short period of time calcining (1-2 hour) method spraying chromic oxide.

oxygenant is the cationic hexavalent chromium compound of containing metal, and oxidant concentration is on 40g/l, and small molecules aldehyde, alcohol are reductive agent; Do not need tensio-active agent; React in closed system, temperature is generally at 140 ~ 300 DEG C, and the reaction times is 1 ~ 120min; The intermediate obtained needs calcining, and calcining temperature is generally at 800 ~ 1200 DEG C, and calcination time is generally 1 ~ 2h.

A kind of method preparing spraying chromic oxide provided by the invention, its step is as follows:

1) first the cationic hexavalent chromium compound of a certain proportion of oxygenant containing metal, reductive agent small molecules aldehyde or alcohol, mix with appropriate water, then join in autoclave, and be sealed to closed system;

2) general reductive agent: oxygenant (mol/mol)=0.2 ~ 5;

3) seal, make reaction system become closed system;

4) be warmed up to appointment temperature of reaction T, and the reaction times is at the reaction temperatures set; General reactions temperature range is 140 ~ 300 DEG C; The General reactions time is less than 120min;

5) after reaction terminates, take out the precipitation obtained, through washing, drying, then at design temperature calcining certain hour, obtain being similar to spherical micron order spraying chromic oxide.

6) calcining temperature is generally at 800 ~ 1200 DEG C, and calcination time is generally 1 ~ 2h.

With existing technique ratio, advantage of the present invention is:

Calcination time shortens a lot (being reduced to below 2h from more than 10h), do not need that tensio-active agent, technique are simpler, energy consumption reduces a lot, quality product and is easier to control.

Embodiment

Embodiment 1:

1.8 ~ 3g K ₂crO ₄, 0.2 ~ 0.6g methyl alcohol mixes with 30g water, react in closed system, temperature 180 ~ 240 DEG C, the reaction times is 60min; After reaction terminates, take out the precipitation obtained, through washing, 110 DEG C of dryings, then at 1000 DEG C of calcining 2h, obtain being similar to spherical micron order spraying chromic oxide.

Embodiment 2:

2 ~ 3.5g K ₂crO ₄, 0.3 ~ 1.0g formaldehyde mixes with 30g water, react in closed system, temperature 180 ~ 240 DEG C, the reaction times is 60min; After reaction terminates, take out the precipitation obtained, through washing, 110 DEG C of dryings, then at 1000 DEG C of calcining 2h, obtain being similar to spherical micron order spraying chromic oxide.

Embodiment 3:

2.2 ~ 4g Na ₂cr ₂o ₄, 0.2 ~ 0.7g methyl alcohol mixes with 30g water, react in closed system, temperature 180 ~ 240 DEG C, the reaction times is 60min; After reaction terminates, take out the precipitation obtained, through washing, 110 DEG C of dryings, then at 1000 DEG C of calcining 2h, obtain being similar to spherical micron order spraying chromic oxide.

Claims

1. simply prepare a method for spraying chromic oxide, it is characterized in that oxygenant, reductive agent, do not need tensio-active agent, react under hydrothermal conditions, the intermediate obtained obtains spraying chromic oxide after calcining, and concrete preparation process is as follows:

1) first the cationic hexavalent chromium compound of a certain proportion of oxygenant containing metal, reductive agent small molecules aldehyde or alcohol and appropriate water are mixed, then join in autoclave, and be sealed to closed system;

2) appointment temperature of reaction is warmed up to, the reaction regular hour;

3) after reaction terminates, take out the precipitation (intermediate) obtained, through washing, drying, then at design temperature calcining certain hour, obtain being similar to spherical micron order spraying chromic oxide.

2., according to claim 1, it is characterized in that oxygenant is the cationic hexavalent chromium compound of containing metal, reductive agent is small molecular alcohol or aldehyde.

3., according to claim 1, it is characterized in that oxidant concentration is on 40g/l.

4., according to claim 1, it is characterized in that water-heat process does not need tensio-active agent.

5. according to claim 1, it is characterized in that reductive agent: oxygenant (mol/mol)=0.2 ~ 5.

6. according to claim 1, it is characterized in that reacting in closed system, temperature is generally at 140 ~ 300 DEG C, and the reaction times is 1 ~ 120min.

7., according to claim 1, it is characterized in that the intermediate obtained needs calcining, calcining temperature is generally at 800 ~ 1200 DEG C, and calcination time is generally 1 ~ 2h.